1. Field of the Invention
This invention relates in general to an apparatus and method for unwinding and cutting a uniform length of material from a fabric and in particular to a new and useful device and method for aligning boundary edges between lengths of fabric of varying thicknesses.
2. Description of the Prior Art
The invention relates to a system for the aligning and thread-true severing of fabric webs having a thickness differing in a longitudinal direction, for example, terry cloth with alternate napless lanes and lanes with nap extending crosswise to the longitudinal direction. In unwinding fabric webs from supply rolls it happens frequently that the web is distorted in itself, that is, in fabric webs made of warp and weft threads the weft threads run obliquely and/or crookedly.
In a known system (Swiss Pat. 1 22 573) for the thread-true cutting of fabric webs, the fabric web, retained at one end but otherwise freely resting on a table top, is smoothed during severing by means of a brush preceding the knife and is aligned thread-true by a needle positioned before the knife in the prolongation of the cutting line and engaging into the thread lane between two weft threads. This method, however, will give reliable results only if the fabric web has relatively thick and smooth weft threads, which form relatively deep and even thread lanes. Besides, the fabric web to be aligned must not be too large or too heavy, as otherwise there is danger that the aligning needle will not align the fabric web thread-true in the desired manner, but will run over the weft threads sideways.
In another known system (German Disclosure 1,535,999) for the thread-true severing of fabric webs provided with tear-line weft threads, a carriage movable crosswise to the pull off direction is arranged, which carries a second carriage displaceable parallel to the pull off direction by manual rotation of a shaft. A severing device comprising a circular knife is arranged on the second carriage. With the second carriage are connected two needle strips present below the fabric web laid out flat, one of which is arranged to the left and the other to the right of the cutting line. The needle strips carry pivotable needle holders which are held first in an inoperative position. During cutting, the needle holders are released successively by release pins arranged in the vicinity of the circular knife, owing to which the needle holders swing up and the correlated needles penetrate into the fabric web, retaining it. If the way the tear line weft thread runs is crooked or not at right angles, then during the displacement movement of the first carriage, the second carriage with the severing device and the needle strips is continuously made to flow the tear line weft thread by rotation of said shaft. While it is true that in this way it is achieved that the cutting line runs parallel to the tear line weft thread and the cutting edges are aligned in a straight line, the system for the practice of this method is exceedingly expensive and complicated in comparison to the first-named system. In addition, the continual manual comparing between the course of the tear line weft thread and the respective cutting line of the severing knife and the possibly necessary shifting of the second carriage requires a steady high attention of the operator, soon resulting in fatigue, which may cause faulty working.